Security in Computing, Third Edition

7.1. Network Concepts

To study network threats and controls, we first must review some of the relevant networking terms and concepts. This review does not attempt to provide the depth of a classic networking reference, such as [GAL99] or [TAN03]. In earlier chapters, our study of security focused on the individual pieces of a computing system, such as a single application, an operating system, or a database. Networks involve not only the pieces but also—importantly—the connections among them.

Networks are both fragile and strong. To see why, think about the power, cable television, telephone, or water network that serves your home. If a falling tree branch breaks the power line to your home, you are without electricity until that line is repaired; ...